Modeling for speed-boats.



PATENTED JUNE 1l l J. E. TWIGG. MODELING EOE SPEED EoATs.

.APPLICATION FILED FEB. 12, 1906.

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JOHN F. TWIGG, OF SAN FRANCISCO, CALIFORNIA.

MODELING FOR SPEED-BOATS.

Specification of Letters Patent.

Patented June 11, 1907.

Application filed February l2, 1906. Serial No. 300,633.

To all whom t may concern:

Be it known that I, JOHN F. Twice, a citizen ofthe United States, residing at the city and county of San Francisco and State of California, have invented new and useful Improvements in Modeling for Speed-Boats, of which the following is a specilication.

My invention relates to modeling, and lines for laying out, the under water body of boats and vessels, especially those designed for high speed.

The invention consists in the means and method for laying out and shaping the lines of the boat and making the model of the same, the details of which will be more fully explained by reference to the accompanying drawings, in which- Figure l shows one method of carrying out my invention by means of a quarter circle. Fig. l is also readable as a cross section of the quarter cylinder of Figs. 2, el and 5. Figs. 2, 4 and 5 represent dii-ferent views of a quarter cylinder for attaining the ends of the invention, Fig. 5 being a perspective view of a quarter cylinder, showing origin and relations of lines of model or boat to same; Fig. 2 shows elevation of quarter cylinder with general elevation of body of model in relief Fig. 4 shows plan of quarter cylinder and water line. Fig. 3 shows a simple practical rule for applying the principle of Figs. 1, 2, 4, 5 to gain the same end.

The object of the present invention is to produce an under water body for boats and vessels which will oiler the least possible resistance when being propelled or moved through the water, especially at high speed. This object I have discovered maybe achieved by a variety of methods; each method however embodying the same underlying principle. If an arc of 9()O is described, and a chord drawn to connect the ends of the are, and two radii 90O from each other drawn to the ends of the arc, and a line drawn from the centery of the chord to intersect the arc and parallel with either of said radii, it will be found that the radius of the arc will be 2.74-1- (approximately 2.7 5) times the length of said intersecting line. This fact is made use of by Ine in determining the various lines in the length, breadth and depth of a vessel the aforesaid intersecting line drawnfrom the center ofthe chord corresponding in all cases to the half'breadth of the boat amidships.

,In the practical application of the invention by one method I take a quarter circle (Fig. l) having a radius which is equal to about 2.75 times the half breadth of the amidships section on water line of the boat to be constructed. The radii C B, C A, are drawn to the ends of the arc and the ends of the arc are connected by the chord B A. The lines C B, C A are divided into equal parts (as many parts as are necessary for the ordinates or sections in length of water line of boat.) There are sixteeen of these sections shown in the present invention. One set of vertical lines are drawn from these division points on C B parallel with C A; and a second set of horizontal lines is drawn from the dividing points on C A parallel with C B. The portions of the vertical lines lying between the chord B A and the arc shall be the depth from water line to center keel line at each respective section or ordinate of the boat; and the portions of the horizontal lines included between the chord and arc shall be the half breadth on water-line of each respective seetion or ordinate of the boat. The outline of the arc between the termini of any two hori Vzontal and vertical lines which cross each other on the locus of A B, or in other words the portion of the arc between a half breadth line and a corresponding draft line will be the vertical outline of the respective section of the boat; thus, referring to Fig. l, B is the fore end of water line, and A the after end of water line. The length of the line lil-lb, gives the draft line on the forward section, and the horizontal line lu-1C, gives the half breadth of the forward section 5 and the arc 10-1b, gives the length and curve of the vertical outline of the forward section of the boat and so correspondingly with each ofthe other sections. It will be found that the coefficient of the block measurement of this body will be approximately 34 per cent. that is, the width at midship section multiplied by depth and result multiplied by length of water-line, the displacement of boat would be 34 per cent of the whole.

The same results may be obtained by taking a quarter cylinder, as shown in Figs. 5, 2, 4. This quarter cylinder shall have a length approximately equal to the length of the water line body, and shall have a radius equal approximately to 2.75 times the width of the amidships section of the boat on water line. This cylindrical segment is intersected diagonally by two planes at right angles to each other, as shown in Fig. 5; one

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other on the straight dotted line A B, and l producing a cylindrical segment having a curved spirally formed surface, pointed at the ends. The straight dotted Aline A B is divided into equal parts la, 2' etc., as many parts as are necessary for the ordinates or sections in length of water line of boat. Also the surface of the quarter cylinder is divided lengthwise by a series of arcs lying in imaginary planes parallel with the end of the cylinder into a corresponding number of sections or ordinates. The portions of these arcs, as

15b-15, 14h-14C, &c. included between the upper .and lower curved lines A, 15C, B and A 15b B gives the vertical contour line of a correspondng section of the boat. The heavy lines of Fig. 5 show the boat; the curved line A, 8C B gives the water line of the boat, and the lower curved line A 8b B, corresponding to the keel line, B being the bow and A the stern of the boat; the lines l5-15, 14de-44a giving a section of the boat, and the lines 15a-15b, 14a-14`0, giving the depth of water line of the sections of the boat, similarly as described in connection with Fig. 1.

Another method of achieving the same result is shown in Fig. 3. In this case I draw the line E F equal in length to the water line of the boat, and divide this line into .equal sections, corresponding to the sections -or ordinates of the boat. From a point midway betwen E and F I erect a line D B perpendicular to E F, as at C. From C as a center I measure on C B, and also on E F at both sides of C, a distance equal approximately to 2.75 times the half breadth of the amidship section of boat, as shown by A C, C A, C B. v points A B A are connected as shown, l

The and the lines A B, B A are divided off into as many equal parts as there are sections or ordinates of the boat, and correspondingly with the divisions of E F previously men tioned. From these divisional points arcs' are described having a radius equal to C B, these arcs or scribe sections extending from E F to C D. For convenience I put the amidship section and forward body on one side, as for example on the right, and the after body on the other. side of the line C D. The distance from C to where the several arcs intersect C D give depth of the respective sections of the boat; these distances being measured off at right angles to the ordinates on E F, and a line drawn through the termini of these lines gives the curved line E D F which is center keel line. The distance from C to points of intersection of the arcs with the line E F shall be the half breadth on water line of corresponding sections.

The vresul-ts `of .all the foregoing methods half breadth of the corresponding are identical and the same principle'present in each. A view of the body of a model' looking lengthwise will show the bottom in the form of a twisted spiral formed on the face of a cylinder as indicated in Fig. 3.

In all cases the transverse sections would all be circular curves; the bow of the boat will be approximately vertical, and the amidship section practically at an angle of 45 and the continuation aft of the curved lines or sections will gradually assume :a ,substantially horizontal section at the stern.

The amidship section of my boat will have a depth of half the width of the same section on the water-line. The deepest .point of the boat will be about one-quarter of the length of the boat from bow, .and the widest point on the water-line will be about one-quarter of length from stern.

This model it is to be understood represents the under water body of the vessel; above the Water-line the hull may be :extended in various shapes :and proportions fornecessary stability, sea-worthiness, room, etc., shown by dotted lines in Fig. 3. M

It will be observed by reference to the drawings that in any under Water body :designed according to the principle of this linvention, whether for large or small vessel, the amidship section will necessarily bear the same proportion and relation toa corresponding quarter circle or quarter cylinder.

Having thus described my invention, what I claim and desire to secure by Letters Patent is- 1. A boat or vessel having an under Water body, the lines of which pass through inten sections of 4ordinates .and horizontal divisions -of a quarter of acircle having va radius approximately two and seventy five hundredths times the half breadth of the boat amidships on the water line.

2. In a boat .or vessel, an under water body formed by equally spaced parallel horizontal and vertical lines intersecting the chord lof sa `quarter of a circle fand each other, the intersection of lsaid horizontal lines with the arc determining the half width on the water line, and the length of the cor-responding vertical lines from their junction with the chord ,and the horizontal line to 'the arc, giving the depth .to the center keel line.

3. In a boat or vessel, an underwater body formed by intersections -of a chord of a quarter of a circle having ya radius of yapproximately times the half breadth of the boat amidships, with equally yspaced horizontal and vertical lines intersecting each other :and the chord, said lines being parallel with 'corresponding radii connecting the endsof theate,

said vertical and horizontal lines bei-ng -extended to intersect the arc, land including the curvature of the boat surface between 'the vertical and horizontal lines.

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twoand seventy five hundredths 4. In a boat or vessel, an under water body formed by intersections of a chord of a quarter of a circle having a radius of approximately t'Wo and seventy ive hundredths times the half breadth of the boat amidships, with equally spaced horizontal and vertical lines intersecting each other and the chord, said lines being parallel with corresponding radii connecting the ends of the arc, said vertical and horizontal lines being extended to intersect the arc, and the portions of said horizontal lines between the chord and arc corresponding to the half breadth of the sections of the boat.

5. In a boat or vessel, an under water body formed by intersections of a chord of a quarter of a circle having a radius of approximately two and seventy five hundredths times the half breadth of the boat amidships, with equally spaced horizontal and vertical lines intersecting each other and the chord, said lines being parallel with correspending radii connecting the ends of the arc, said vertical and horizontal lines being extended to intersect the are, and the portions of said vertical lines between the chord and arc corresponding to the depth of the sections of the boat from the water line.

6. A boat or vessel having the Linder water lines conforming to the surface of a quarter cylinder, with the bow practically vertical, and Wave lines continuing' aft in a spiral formed on the surface of the cylinder, and terminating at the stern on an approximately horizontal line.

7. In boat building and designing, an under-Water body whose surface outlines correspond to arcs on a segment of a cylinder, said segment made by two intersecting planes disposed at right angles to each other, and extending diagonally of the cylinder, and from the same points of origin thereon, said points of origin lying in planes perpendicular to each other and the line of intersection of said planes being the axis of the cylinder.

S. In boat building and designing, an underneath body, whose surface lines at the ordinates or sections of the boats length correspond to arcs on a segment of a quarter cylinder said quarter cylinder having a length equal to the water line of the boat and a radius equal approximately to 2.75 times the half breadth of the midship section, said segment of the cylinder' included between two planes perpendicular to each other and running diagonally of the cylinder from the same points of origin, said points of origin lying at the ends ofthe quarter cylinder, in the planes of the flat sides thereof.

9. In a boat or vessel, an under-water body whose vertical lines lie in circular curves on a cylinder, the curve oi the midship section of said boat having a radius approximately 2.75 times the halt breadth of said section.

l0. In a boat, an under-water body whose vertical lines lie in circular curves and whose fore and aft lines lie in a twisted spiral on the face of a cylinder, the curve of the midship section of said boat having a radius approximately 2.75 times the half breadth of said section.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

JOI-IN F. TWIGG. Witnesses:

S. H. NoURsE, D. B. RICHARDS. 

